docs: def log_stack(logger, level=logging.INFO, limit=None, frame=None):
      """
      Display the current stack on ``logger``.
  
      This function is designed to be used during emission of log messages, so it
      won't call itself.
      """
      if showing_stack.inside:
          return
      showing_stack.inside = True
      try:
          if frame is None:
              frame = sys._getframe(1)
          stack = "".join(traceback.format_stack(frame, limit))
          for line in (l[2:] for l in stack.split("\n") if l.strip()):
              logger.log(level, line)
      finally:
          showing_stack.inside = False